Terminal wire blocks are widely used to connect electrical wires to printed wiring boards (PWBs) or printed circuit boards (PCBs), to securely couple pairs of wires, and to otherwise provide reliable electrical contacts. In general, it is known to use either spring clamps or screw clamps as terminal wire blocks to secure electrical wires in a fixed position.
Spring wire clamps typically include a housing and a spring (or a similar elastic component) to which a force is manually applied as a wire is inserted into the clamp. Once released, the spring exerts a force on the wire to push the wire against one of the walls of the housing. It is also known to install an elastic element on the wire to interact with a clamp housing of a standard size. For example, a typical personal computer includes a cage terminal to receive an Ethernet cable that includes a flexible plastic strip, bent to define an acute angle, at one or both ends. The plastic strip and the cage terminal together define a push-in terminal that does not require screws, bolts, or other fasteners.
By contrast, screw clamps typically include a housing and an externally threaded fastener such as a screw operatively connected to the housing. A technician places a wire inside the housing and tightens the fastener to push the wire against one of the walls of the housing. Accordingly, screw clamps usually require the use of a tool such as a screwdriver.
Some technicians prefer spring clamps while others prefer screw clamps. In addition to personal preferences, certain applications make spring clamps preferable because spring clamps normally do not require special tools or room to maneuver such tools. Moreover, spring clamps typically are better suited for connecting wires on or adjacent to vibrating devices, as threaded connections (e.g., a screw and a nut) tend to loosen in response to vibration. On the other hand, spring clamps may include easily breakable components such as plastic strips, or may age faster as springs or similar flexible components lose rigidity or elasticity.